[Date Index] [Thread Index] [Author Index]

Re: How to get non-printing heads?

• To: mathgroup at smc.vnet.net
• Subject: [mg46998] Re: How to get non-printing heads?
• From: "Peter Pein" <no at spam.no>
• Date: Fri, 19 Mar 2004 01:35:51 -0500 (EST)
• References: <c388k0$bnb$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

"kj" <socyl at 987jk.com> schrieb im Newsbeitrag
news:c388k0$bnb$1 at smc.vnet.net...
>
> How can I give a Mathematica object a different head?
>
> I tried
>
>   In[1]:= Head[a] ^= Constant;
>
> But, as shown below, this doesn't work as desired:
>
>   In[2]:= MatchQ[a, _Constant]
>
>   Out[2]= False
....

In[1]:= a = Constant["a"];
        a^2 + b^2
Out[2]= b^2 + Constant[a]^2
In[3]:= Unprotect[Constant];
        Format[Constant[x_String]] ^=  x;
        Protect[Constant];
        a^2 + b^2
Out[5]= b^2 + a^2
In[6]:= Head[a]
Out[6]= Constant

might do what you want
-- 
Peter Pein, Berlin
petsie at arcAND.de
replace && by || to write to me